An engineer checks JPL's Aquarius instrument.

An engineer checks JPL's Aquarius instrument.

In the image above, JPL's Aquarius instrument is prepped for shipment to Argentina on June 1. The mission will study how salt affects ocean circulation, the water cycle and climate.

Scheduled for launch in May 2010, Aquarius will be the first NASA instrument to measure sea salinity from space. Scientists believe that big shifts in salinity could be a warning that more severe droughts and floods are on their way or even that global warming is speeding up.